1. Field of the Invention
This invention relates to a process for the production of cinnamic acid esters. More specifically, it relates to a process for the production of cinnamic acid esters which comprises oxidatively carboxylating a styrene in the presence of an alcohol.
2. Description of the Prior Art
Cinnamic acid is used not only as a perfume starting material together with cinnamic aldehyde, cyclamen aldehyde, .beta.-amylcinnamic aldehyde etc. but also as a starting material for agricultural chemicals, and, on a laboratory basis, this may be produced by Perkin reaction.
The process for the production of cinnamic acid esters by the oxidative carbonylation of styrene is disclosed in, for example, Japanese Patent Application Laid-open Nos. 40709/1978, 15242/1981, 22749/1981, 22750/1981, 71039/1981, 21342/1982, 21343/1982, 70836/1982 etc.
In Japanese Patent Application Laid-open No. 15242/1981, there is used a catalyst comprising (1) a platinum group metal or a compound thereof, (2) a copper salt or an iron salt and (3) an organic acid salt of a metal selected from alkali metals, alkaline earth metals and aluminum group metals.
Japanese Patent Application Laid-open No. 70836/1982 discloses a catalyst system comprising (1) a platinum group metal or a salt thereof, (2) a salt of copper or iron, (3) one or more compounds selected from hydroxides, carbonates and acetates of alkali metals and alkaline earth metals in an ethylene glycol-ether based solvent.
Furthermore, Japanese Patent Application Laid-open No. 49709/1978 relates to the oxidative carbonylation reaction, which is the reaction mode in the present invention, but in the examples of said application, the selectivity to unsaturated carboxylic acid esters is extremely low and the catalyst in said system is composed of a solid catalyst of a group VIII noble metal single substance supported on a support.